Hello!
I know Ka refers to the dissociation of an acid, but am confused about why we would take the negative log of this. Could someone clarify the meaning of pKa and its significance?
pKa Clarification
Moderators: Chem_Mod, Chem_Admin
-
- Posts: 102
- Joined: Fri Sep 24, 2021 6:53 am
- Been upvoted: 1 time
Re: pKa Clarification
Hi! pKa helps you tell how weak or strong an acid is. We take the -log because it helps give us an easy number to work with. It's the same reason we use logarithms to find pH. It's much easier to write a pH of 14 than 1.0 * 10^-14. It's just a convenience thing! Hope that helps.
-
- Posts: 117
- Joined: Fri Sep 24, 2021 6:45 am
Re: pKa Clarification
Hi!
pka also allows the calculations that you perform with the value to become much easier as it makes working with a value like 9 better than x 10^-9
pka also allows the calculations that you perform with the value to become much easier as it makes working with a value like 9 better than x 10^-9
-
- Posts: 100
- Joined: Fri Sep 24, 2021 5:17 am
Re: pKa Clarification
Ka values are often annoying to deal with because of the negative exponents, so it's easier to work with pKa where we get small positive numbers that are easier to quantify and understand.
-
- Posts: 101
- Joined: Fri Sep 24, 2021 5:42 am
Re: pKa Clarification
Using -log for both pKa and pH are just to make the numbers easier to work with. You often get really small values for Ka that have negative exponents, so taking the -log makes it a much cleaner number.
Return to “Calculating pH or pOH for Strong & Weak Acids & Bases”
Who is online
Users browsing this forum: No registered users and 7 guests